Hello there. I have a simple differential equation (diff(y(x), x)+1)*exp(y(x)) = 4 , in which I want to got a partial solution (find a value of constant) for y(1)=0. How do I do that? I've checked help on pdsolve function and it's too complicated for me to understand something. Examples do not contain anything such simple as that. Thanks in advance.

I have in mind all the real roots of the equation 2*tan(Pi*t^2)-tan(Pi*t)+tan(Pi*t)*tan(Pi*t^2)^2 = 0.

Maple fails with it:

>RealDomain:-solve(2*tan(Pi*t^2)-tan(Pi*t)+tan(Pi*t)*tan(Pi*t^2)^2 = 0, t);

RootOf(tan(_Z)*tan(_Z^2/Pi)^2-tan(_Z)+2*tan(_Z^2/Pi))/Pi

 Even its numerical solution has gaps.

>Digits := 15; a := Student[Calculus1]:-Roots(2*tan(Pi*t^2)-tan(Pi*t)+tan(Pi*t)*tan(Pi*t^2)^2 = 0, t = -2 .. 2);
Warning, some roots are returned as numeric approximations
 [-1.35078105935821, -1.18614066163451, -1.00000000000000, 0, 

   1.00000000000000, 1.28077640640442, 1.68614066163451,    1.85078105935821]

>nops(a);

8

>b := Student[Calculus1]:-Roots(2*tan(Pi*t^2)-tan(Pi*t)+tan(Pi*t)*tan(Pi*t^2)^2 = 0, t = -2 .. 2, numeric);
 [-1.35078105935821, -1.18614066163451, -1.00000000000000, 

   -0.780776406404415, 0., 1.00000000000000, 1.28077640640442, 

   1.68614066163451, 1.85078105935821, 2.00000000000000]
>nops(b);
                               10

whereas 

>plot(2*tan(Pi*t^2)-tan(Pi*t)+tan(Pi*t)*tan(Pi*t^2)^2, t = -2 .. 2);

shows 14 solutions.

The output of the command

>identify(a);

[1/4-(1/4)*sqrt(41), 1/4-(1/4)*sqrt(33), -1, 0, 1, 1/4+(1/4)*sqrt(17), 1/4+(1/4)*sqrt(33), 1/4+(1/4)*sqrt(41)]

suggests a closed-form expression for the roots.

i want to write the result of a calculation to a file in a way that i can be able to call them later. for example :

restart;
n := 40; h := 40;
a := h*i/(2*n);

sys1 := [diff(x(t), t) = 2*t+1, diff(y(t), t) = 1+5*t, x(0) = 1, y(1) = 0];

for i from 0 by .5 to 1 do res := dsolve(sys1, numeric); res(a) end do;
 

i would like to write just the values of t and y(t) to a file/vector or whatever.

Thx in advance

Dear sir

In my ode problem i do not know that how to set range (eta) from -2 to 2 please can  you help me.

Consider the following expression obtained from the solve command: Note that this uses the two variable arctan function.

p:=arctan((-cos(theta)^3-(1/2)*cos(theta)^2-(1/2)*cos(theta)*((2*cos(theta)+1)*(2*cos(theta)-3)*(cos(theta)+1)^2)^(1/2)+2*cos(theta)-(1/2)*((2*cos(theta)+1)*(2*cos(theta)-3)*(cos(theta)+1)^2)^(1/2)+3/2)^(1/2), -(1/2)*cos(theta)-1/2-(1/2)*((2*cos(theta)+1)*(2*cos(theta)-3)*(cos(theta)+1)^2)^(1/2)):

#ploting the expression shows a non-zero value at theta = Pi,  however if I convert p to a function using

f:=unapply(p,theta):

# then f(Pi);  gives a value of 0

#On the other hand maximize(p,theta=3*Pi/4..5*Pi/4,location); shows a non-zero value of 4*Pi/5 at theta = Pi,  which agrees with the plot of p, namely, it returns:

-arctan((10-2*5^(1/2))^(1/2)/(5^(1/2)+1))+Pi,

{[{theta = Pi}, -arctan((10-2*5^(1/2))^(1/2)/(5^(1/2)+1))+Pi]}

Is this a bug? Or what?

Thanks, 

Edwin

Hello

I wonder whether someone out there would give some ideas on how to implement a problem involving monomials (or polynomials if you wish).

dx/dt=f(x,y,z), dy/dt=g(x,y,z) and dz/dt=h(x,y,z) where f, g and h are polynomial functions of x,y,z.   

For instance, I need a test that returns false in:

a) dx/dt=f(x,z), dydt=anything, dz/dt=h(x,z) or 

b) dx/dt=f(x,y), dydt=g(x,y), dz/dt=anything.

c) dx/dt=anything, dy/dt=g(y,z), dz/dt=h(y,z)

that is, if two derivatives are related only between themselves, a false should be returned.  An example where a false should be returned is

[x*y*theta[5]+x*theta[2], x*y*theta[15], x*theta[22]+y*theta[23]+z*theta[24]] = [f(x,y),g(x,y),h(x,y,z)] where theta[5] .. theta[24]  are the coefficients.  

Many thanks.

Ed

PS. I am trying to avoid "for" in the solution in case I need to add another derivative but could not come up with a solution. In that case I need to test 3 variables instead of 2 and then 2 variables (as in the examples).

For my fdiff graph, it seems that the cirtical points appear to be jaggered or not smooth. Anyone nows what seem to be the problem? i tried increasing the numpoints but it did not work:( I am open to all opinions. Thanks:)

fyp2.mw

Hi, 

 I use Maple/MapleSim 2016. I have a question about how to save compiled modules as an one set. (Picture below describes my question.)

I use the Maple command "GetCompiledProc" to obtain the compiled module of MapleSim Model. And then, in some cases, I need to make a lot of compiled modules by using one MapleSim model.

(Usually, I make different compiled modules which contain different parameters to others)

For the convenience of using different compiled modules, I want to make these contained in one set whose name is "ModelSet". ("Case1 -> Case2" in the picture)

I tried this, but it did not work. Please see the attached (simple) model and the Maple worksheet in that model.

[TS]CompiledMoule_Practice.msim

For example, I want to use Model1(Compiled module 1) by loading that module from the ModelSet[1]. (Similarly, Model2 by loading ModelSet[2].)

However, when I load one of them, it is not the compiled module, but just a "symbol". It does not work as a compiled module any more.

Is there any way to make the "ModelSet" as I want? In fact, I tried to make the type of ModelSet as vector, list, and set, but all of them did not work. 

I appreciate any idea you may have.

> restart;
> with(plots);
> n := [0, .5, 1, 5]; pr := .71; p := 0; l := [1, 2, 3]; b := 0; s := 0; L := [green, blue, black, gold];
                         [green, blue, black, gold]
> R1 := 2*n/(n+1);
                              2 [0, 0.5, 1, 5]
                             ------------------
                             [0, 0.5, 1, 5] + 1
for j from 1 to nops(l) do; for j from 1 to nops(n) do        R1 := 2*n[j]/(1+n[j]);        R2 := 2*p/(1+n[j]); sol1 := dsolve([diff(diff(diff(f(eta),eta),eta),eta)+f(eta)*diff(diff(f(eta),eta),eta)+R1*(1-diff(f(eta),eta)^2) = 0, (1/pr)*diff(diff(theta(eta),eta),eta)+f(eta)*diff(theta(eta),eta)-R2*diff(f(eta),eta)*theta(eta) = 0, f(0) = 0, (D(f))(0) = l+b*((D@@2)(f))(0), (D(f))(-2) =1, theta(0) = 1+s*(D(theta))(0), theta(-2) = 0], numeric, method = bvp); fplt[j]:= plots[odeplot](sol1,[eta,diff(diff(f(eta),eta),eta)],color=["blue","black","orange"]);         tplt[j]:= plots[odeplot](sol1, [eta,theta(eta)],color=L[j]); fplt[j]:= plots[odeplot](sol1,[eta,diff(f(eta),eta)],color=L[j]);      od:od:

Error, (in dsolve/numeric/bvp) unable to store 'Limit([eta, 2*eta, 3*eta]+eta^2*[.250000000000000, .500000000000000, .750000000000000]-.250000000000000*eta^2, eta = -2., left)' when datatype=float[8]
> plots:-display([seq(fplt[j], j = 1 .. nops(n))], color = [green, red], [seq(fplt[j], j = 1 .. nops(l))]);

> sol1(0);

Dear sir

In the  above problem i tried to write a nested program but its not executing and showing the error as Error, (in dsolve/numeric/bvp) unable to store 'Limit([eta, 2*eta, 3*eta]+eta^2*, i want the plot range from -2 to 2 but taking only 0 to -2 ,and -2.5 to 3 but taking only 0 to 1

Hi,

I want to write my first module, and I failed!  I create an instance of the class (module?)

myList := TestModule(3);                    # works.

But I've no acess to the members, since I use export! What's wrong?

myList:-get_n;
myList:-set_n(20);
myList:-run();

Error, `myList` does not evaluate to a module
Error, `myList` does not evaluate to a module
Error, `myList` does not evaluate to a module

# *****************************************************************************

TestModule := module()
    export get_n, set_n, run;
    local  n, result, ModuleApply, profileRun;
    option package;
    description "A testmodule";

    # Constructor
    ModuleApply := proc(n)
        print("Calling of Module Apply...");
         thismodule:-n := n;
         result := [];
         profileRun();
         return result;
     end proc:

    # Implementation of member run
     run := proc()
         print("Calling of run...");
         dummy := [];
         for i from 1 to 20000 do
            dummy := [op(dummy), i]
         end do;
         result := TRUE;
    end proc;
    
    # Implementation of member runprofile;
     profileRun := proc()
          print("Call of profileRun...");
          CodeTools[Profiling]:-Profile(run);
           run();
           CodeTools[Profiling]:-PrintProfiles(run);
           CodeTools[Profiling]:-UnProfile(run);
     end proc;

     # getter
     get_n := proc()
         n;
     end proc;

     # setter
     set_n := proc(n)
         thismodule:-n := n;
     end proc;
     
end module;

Dear all!

Hope everything going fine with you. I am facing problem to integrate the attached file in this file we need the result of z[1] and others like y[1]. I am waiting your quick answer.

Help.mw

With my best regards and sincerely.

Muhammad Usman

School of Mathematical Sciences 
Peking University, Beijing, China

Email: muhammadusman@pku.edu.cn

Mob #: 0086-13001903838

Dear All

I am stucked at converting an differential expression in Jet notations. Maple is giving error as  expression contains composite derivatives. Please see attached file.

Download Composite_Derivative.mw

I have written a C++ program which I feed in an input from Maple which has been converted using the CodeGeneration package in Maple and stored in a text file. For it to be processed in C++ I need to remove the cg = at the start of the Maple output expression. An example of this is as follows:

C(x^2+y^2+z^2);

cg = x * x + y * y + z * z

C++ cannot process the cg= at the start of the string and so I have found ways around it by using Bash or C++ itself to remove or ignore the cg = but I was wondering if it was possible to just not have Maple print it to begin with?

- Yeti

I have looked everywhere for help on how to format decimals to indicate they are recurring; or there is a set of numbers that is recurring. Normal notation would show a point above the the appropriate digits that follow the decimal point to indicate recurrence.

I'm sure it is simple to do but I cannot find the help that I need from the Maple help.

Regards, DLW

hi

please help me for solve this equations?

thanksazizi.mw
 

Download azizi.mw